Currently, ozone is being discussed in dentistry as a possible alternative oral antiseptic agent. Its high antimicrobial power, also against oral pathogens, without resistance development has been reported not only for gaseous ozone (Paraskeva and Graham, 2002; Baysan and Lynch, 2004) but also for ozone in aqueous solution (Restaino et al., 1995; Nagayoshi et al., 2004a,b; Arita et al., 2005). Ozone gas has been found to significantly decrease the viability of oral cells in the currently used concentrations in dentistry. In comparison, aqueous ozone revealed a high level of biocompatibility to fibroblasts, cementoblasts and epithelial cells (Filippi, 2001; Ebensberger et al., 2002; Nagayoshi et al., 2004b), which suggests its use against oral infectious diseases where it comes into contact with resident oral cells, e.g. marginal and apical periodontitis.
Marginal and apical periodontitis result not from pathogenic bacteria alone but from the interaction of pathogens and host immune response mechanisms (Honda et al., 2006; Nair, 2004). Therefore, the immune-modulatory effect of treatment strategies proposed for these diseases must also be considered. Both disease entities are characterized by an inflammatory reaction involving different oral hard- and soft-tissue compartments, e.g. the marginal gingiva, periodontal attachment fibers or the alveolar bone (Bartold and Narayanan, 2006; Nair, 2004). The inflammatory process is primarily induced by pathogen-associated molecular patterns, particularly by bacterial lipopolysaccharides (Madianos et al., 2005). The subsequent activation of the inflammatory molecular cascade leads to the expression of several proinflammatory cytokines, e.g. interleukin-1, interleukin-8 and tumor necrosis factor (TNF) that ultimately mediate the destruction of the alveolar bone and periodontal connective tissue (Márton and Kiss, 2000; Graves et al., 2000; Gamonal et al., 2000).
The transcription factor NF-κB plays a pivotal role in the regulation of inflammatory/immune processes and apoptosis (Bonizzi and Karin, 2004). Also for the regulation of periodontal/periapical inflammatory reactions and the pathogenesis of periodontitis, the functional activity of NF-κB has been suggested to be of paramount significance (Nichols T C et al., 2001; Sabeti et al., 2005; Bartold and Narayanan, 2006). NF-κB exists as a dimer which is trapped in the cytosol by inhibitory proteins, e.g. IκBA (Bonizzi and Karin, 2004). The NF-κB-system is activated by numerous agents including cytokines (e.g. TNF, interleukin-1) and microbial pathogens/products. The activation of NF-κB is mediated by the IκB kinase complex that phosphorylates IκB which is subsequently degraded by the proteasome. The thus freed NF-κB translocates to the nucleus where it binds to KB sequences in promoters/enhancers thereby regulating the expression of various genes such as interleukin-1/-8 or TNF.
In the publication “Ozonized low density lipoprotein (ozLDL) inhibits NF-κB . . . ”, Cappello et al. disclose the characteristics of LDL exposed to ozone. However, this citation does not disclose monomeric amino acids which have been ozonized. The agent, which is able to inhibit NF-κB-activation is described as being ozonized cholesterol. Furthermore, it is not disclosed that the proteins are being cleaved by ozonisation and, thus, this publication does not disclose monomeric amino acids as indicated above. Furthermore, this publication is silent on a potential anti-inflammatory effect of ozonized amino acids.
US 2003/211465 discloses ozonized polypeptides, however, not monomeric single amino acids. This publication is related to the prevention of HIV (i.e. is related to viral diseases). Again, also this publication is silent on anti-inflammatory effects of the ozonized amino acids.
Huth et al. “Effect of ozone on oral cells compared with established antimicrobials” describes the antimicrobial effect of ozonized water. However, again, ozonized monomeric amino acids are not disclosed and, furthermore, it is not disclosed that they have an anti-inflammatory effect.
Ozone gas is known to activate NF-κB under certain conditions (Haddad et al., 1996; Laskin et al., 2002). However, it is not known if aqueous ozone also interferes with the NF-κB-system. This is important, as an activation of NF-κB might adversely affect the therapeutic benefit of aqueous ozone when used e.g. against marginal and apical periodontitis.